Handover mechanism in wireless networks

ABSTRACT

A first base station in a network initiates handover of a wireless device in connected mode to a second base station. The first base station initiates a handover employing a first criterion, if the wireless device is in an active call from a first call category with the first base station. The first base station initiates a handover using a second criterion, if the wireless device is not in an active call from a first call category with the first base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 13/607,870,filed Sep. 10, 2012, which claims the benefit of U.S. ProvisionalApplication No. 61/533,343, filed Sep. 12, 2011, which is herebyincorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present inventionare described herein with reference to the drawings, in which:

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention;

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentinvention;

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention;

FIG. 4 is a block diagram of a base station and a wireless device as peran aspect of an embodiment of the present invention;

FIG. 5 is a block diagram depicting a system for transmitting datatraffic over an OFDM radio system as per an aspect of an embodiment ofthe present invention;

FIG. 6 depicts message flows between a base station and a wirelessdevice as per an aspect of an embodiment of the present invention; and

FIG. 7 depicts wireless device handover between a first base station anda second base station as per an aspect of an embodiment of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present invention enable wireless devicehandover in heterogeneous wireless networks. Embodiments of thetechnology disclosed herein may be employed in the technical field ofwireless communication systems. More particularly, the embodiments ofthe technology disclosed herein may relate to handover in heterogeneouswireless networks.

Example embodiments of the invention may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA (codedivision multiple access), OFDM (orthogonal frequency divisionmultiplexing), TDMA (time division multiple access), Wavelettechnologies, and/or the like. Hybrid transmission mechanisms such asTDMA/CDMA, and OFDM/CDMA may also be employed. Various modulationschemes may be applied for signal transmission in the physical layer.Examples of modulation schemes include, but are not limited to: phase,amplitude, code, a combination of these, and/or the like. An exampleradio transmission method may implement QAM (quadrature amplitudemodulation) using BPSK (binary phase shift keying), QPSK (quadraturephase shift keying), 16-QAM, 64-QAM, 256-QAM, and/or the like. Physicalradio transmission may be enhanced by dynamically or semi-dynamicallychanging the modulation and coding scheme depending on transmissionrequirements and radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention. As illustrated in thisexample, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, SC-OFDM (single carrier-OFDM) technology, or the like.For example, arrow 101 shows a subcarrier transmitting informationsymbols. FIG. 1 is for illustration purposes, and a typical multicarrierOFDM system may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentinvention. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD (frequency divisionduplex) and TDD (time division duplex) duplex mechanisms. FIG. 2 showsan example FDD frame timing. Downlink and uplink transmissions may beorganized into radio frames 201. In this example, radio frame durationis 10 msec. Other frame durations, for example, in the range of 1 to 100msec may also be supported. In this example, each 10 ms radio frame 201may be divided into ten equally sized sub-frames 202. Other subframedurations such as including 0.5 msec, 1 msec, 2 msec, and 5 msec mayalso be supported. Sub-frame(s) may consist of two or more slots 206.For the example of FDD, 10 subframes may be available for downlinktransmission and 10 subframes may be available for uplink transmissionsin each 10 ms interval. Uplink and downlink transmissions may beseparated in the frequency domain. Slot(s) may include a plurality ofOFDM symbols 203. The number of OFDM symbols 203 in a slot 206 maydepend on the cyclic prefix length and subcarrier spacing.

In an example case of TDD, uplink and downlink transmissions may beseparated in the time domain. According to some of the various aspectsof embodiments, each 10 ms radio frame may include two half-frames of 5ms each. Half-frame(s) may include eight slots of length 0.5 ms andthree special fields: DwPTS (Downlink Pilot Time Slot), GP (GuardPeriod) and UpPTS (Uplink Pilot Time Slot). The length of DwPTS andUpPTS may be configurable subject to the total length of DwPTS, GP andUpPTS being equal to 1 ms. Both 5 ms and 10 ms switch-point periodicitymay be supported. In an example, subframe 1 in all configurations andsubframe 6 in configurations with 5 ms switch-point periodicity mayinclude DwPTS, GP and UpPTS. Subframe 6 in configurations with 10 msswitch-point periodicity may include DwPTS. Other subframes may includetwo equally sized slots. For this TDD example, GP may be employed fordownlink to uplink transition. Other subframes/fields may be assignedfor either downlink or uplink transmission. Other frame structures inaddition to the above two frame structures may also be supported, forexample in one example embodiment the frame duration may be selecteddynamically based on the packet sizes.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or resource blocks (RB) (in this example 6 to 100RBs) may depend, at least in part, on the downlink transmissionbandwidth 306 configured in the cell. The smallest radio resource unitmay be called a resource element (e.g. 301). Resource elements may begrouped into resource blocks (e.g. 302). Resource blocks may be groupedinto larger radio resources called Resource Block Groups (RBG) (e.g.303). The transmitted signal in slot 206 may be described by one orseveral resource grids of a plurality of subcarriers and a plurality ofOFDM symbols. Resource blocks may be used to describe the mapping ofcertain physical channels to resource elements. Other pre-definedgroupings of physical resource elements may be implemented in the systemdepending on the radio technology. For example, 24 subcarriers may begrouped as a radio block for a duration of 5 msec.

Physical and virtual resource blocks may be defined. A physical resourceblock may be defined as N consecutive OFDM symbols in the time domainand M consecutive subcarriers in the frequency domain, wherein M and Nare integers. A physical resource block may include M×N resourceelements. In an illustrative example, a resource block may correspond toone slot in the time domain and 180 kHz in the frequency domain (for 15KHz subcarrier bandwidth and 12 subcarriers). A virtual resource blockmay be of the same size as a physical resource block. Various types ofvirtual resource blocks may be defined (e.g. virtual resource blocks oflocalized type and virtual resource blocks of distributed type). Forvarious types of virtual resource blocks, a pair of virtual resourceblocks over two slots in a subframe may be assigned together by a singlevirtual resource block number. Virtual resource blocks of localized typemay be mapped directly to physical resource blocks such that sequentialvirtual resource block k corresponds to physical resource block k.Alternatively, virtual resource blocks of distributed type may be mappedto physical resource blocks according to a predefined table or apredefined formula. Various configurations for radio resources may besupported under an OFDM framework, for example, a resource block may bedefined as including the subcarriers in the entire band for an allocatedtime duration.

According to some of the various aspects of embodiments, an antenna portmay be defined such that the channel over which a symbol on the antennaport is conveyed may be inferred from the channel over which anothersymbol on the same antenna port is conveyed. In some embodiments, theremay be one resource grid per antenna port. The set of antenna port(s)supported may depend on the reference signal configuration in the cell.Cell-specific reference signals may support a configuration of one, two,or four antenna port(s) and may be transmitted on antenna port(s) {0},{0, 1}, and {0, 1, 2, 3}, respectively. Multicast-broadcast referencesignals may be transmitted on antenna port 4. Wireless device-specificreference signals may be transmitted on antenna port(s) 5, 7, 8, or oneor several of ports {7, 8, 9, 10, 11, 12, 13, 14}. Positioning referencesignals may be transmitted on antenna port 6. Channel state information(CSI) reference signals may support a configuration of one, two, four oreight antenna port(s) and may be transmitted on antenna port(s) 15, {15,16}, {15, . . . , 18} and {15, . . . , 22}, respectively. Variousconfigurations for antenna configuration may be supported depending onthe number of antennas and the capability of the wireless devices andwireless base stations.

According to some embodiments, a radio resource framework using OFDMtechnology may be employed. Alternative embodiments may be implementedemploying other radio technologies. Example transmission mechanismsinclude, but are not limited to: CDMA, OFDM, TDMA, Wavelet technologies,and/or the like. Hybrid transmission mechanisms such as TDMA/CDMA, andOFDM/CDMA may also be employed.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present invention.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to some of the various aspects of embodiments, transceiver(s)may be employed. A transceiver is a device that includes both atransmitter and receiver. Transceivers may be employed in devices suchas wireless devices, base stations, relay nodes, and/or the like.Example embodiments for radio technology implemented in communicationinterface 402, 407 and wireless link 411 are illustrated are FIG. 1,FIG. 2, and FIG. 3. and associated text.

FIG. 5 is a block diagram depicting a system 500 for transmitting datatraffic generated by a wireless device 502 to a server 508 over amulticarrier OFDM radio according to one aspect of the illustrativeembodiments. The system 500 may include a Wireless CellularNetwork/Internet Network 507, which may function to provide connectivitybetween one or more wireless devices 502 (e.g., a cell phone, PDA(personal digital assistant), other wirelessly-equipped device, and/orthe like), one or more servers 508 (e.g. multimedia server, applicationservers, email servers, or database servers) and/or the like.

It should be understood, however, that this and other arrangementsdescribed herein are set forth for purposes of example only. As such,those skilled in the art will appreciate that other arrangements andother elements (e.g., machines, interfaces, functions, orders offunctions, etc.) may be used instead, some elements may be added, andsome elements may be omitted altogether. Further, as in mosttelecommunications applications, those skilled in the art willappreciate that many of the elements described herein are functionalentities that may be implemented as discrete or distributed componentsor in conjunction with other components, and in any suitable combinationand location. Still further, various functions described herein as beingperformed by one or more entities may be carried out by hardware,firmware and/or software logic in combination with hardware. Forinstance, various functions may be carried out by a processor executinga set of machine language instructions stored in memory.

As shown, the access network may include a plurality of base stations503 . . . 504. Base station 503 . . . 504 of the access network mayfunction to transmit and receive RF (radio frequency) radiation 505 . .. 506 at one or more carrier frequencies, and the RF radiation mayprovide one or more air interfaces over which the wireless device 502may communicate with the base stations 503 . . . 504. The user 501 mayuse the wireless device (or UE: user equipment) to receive data traffic,such as one or more multimedia files, data files, pictures, video files,or voice mails, etc. The wireless device 502 may include applicationssuch as web email, email applications, upload and ftp applications, MMS(multimedia messaging system) applications, or file sharingapplications. In another example embodiment, the wireless device 502 mayautomatically send traffic to a server 508 without direct involvement ofa user. For example, consider a wireless camera with automatic uploadfeature, or a video camera uploading videos to the remote server 508, ora personal computer equipped with an application transmitting traffic toa remote server.

One or more base stations 503 . . . 504 may define a correspondingwireless coverage area. The RF radiation 505 . . . 506 of the basestations 503 . . . 504 may carry communications between the WirelessCellular Network/Internet Network 507 and access device 502 according toany of a variety of protocols. For example, RF radiation 505 . . . 506may carry communications according to WiMAX (Worldwide Interoperabilityfor Microwave Access e.g., IEEE 802.16), LTE (long term evolution),microwave, satellite, MMDS (Multichannel Multipoint DistributionService), Wi-Fi (e.g., IEEE 802.11), Bluetooth, infrared, and otherprotocols now known or later developed. The communication between thewireless device 502 and the server 508 may be enabled by any networkingand transport technology for example TCP/IP (transport controlprotocol/Internet protocol), RTP (real time protocol), RTCP (real timecontrol protocol), HTTP (Hypertext Transfer Protocol) or any othernetworking protocol.

According to some of the various aspects of embodiments, an LTE networkmay include many base stations, providing a user plane (PDCP: packetdata convergence protocol/RLC: radio link control/MAC: media accesscontrol/PHY: physical) and control plane (RRC: radio resource control)protocol terminations towards the wireless device. The base station(s)may be interconnected with other base station(s) by means of an X2interface. The base stations may also be connected by means of an S1interface to an EPC (Evolved Packet Core). For example, the basestations may be interconnected to the MME (Mobility Management Entity)by means of the S1-MME interface and to the Serving Gateway (S-GW) bymeans of the S1-U interface. The S1 interface may support a many-to-manyrelation between MMEs/Serving Gateways and base stations. A base stationmay include many sectors for example: 1, 2, 3, 4, or 6 sectors. A basestation may include many cells, for example, ranging from 1 to 50 cellsor more. A cell may be categorized, for example, as a primary cell orsecondary cell. When carrier aggregation is configured, a wirelessdevice may have one RRC connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI-trackingarea identifier), and at RRC connection re-establishment/handover, oneserving cell may provide the security input. This cell may be referredto as the Primary Cell (PCell). In the downlink, the carriercorresponding to the PCell may be the Downlink Primary Component Carrier(DL PCC), while in the uplink, it may be the Uplink Primary ComponentCarrier (UL PCC). Depending on wireless device capabilities, SecondaryCells (SCells) may be configured to form together with the PCell a setof serving cells. In the downlink, the carrier corresponding to an SCellmay be a Downlink Secondary Component Carrier (DL SCC), while in theuplink, it may be an Uplink Secondary Component Carrier (UL SCC). AnSCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,is assigned a physical cell ID and a cell index. A carrier (downlink oruplink) belongs to only one cell, the cell ID or Cell index may alsoidentify the downlink carrier or uplink carrier of the cell (dependingon the context it is used). In the specification, cell ID may be equallyreferred to a carrier ID, and cell index may be referred to carrierindex. In implementation, the physical cell ID or cell index may beassigned to a cell. Cell ID may be determined using the synchronizationsignal transmitted on a downlink carrier. Cell index may be determinedusing RRC messages. For example, when the specification refers to afirst physical cell ID for a first downlink carrier, it may mean thefirst physical cell ID is for a cell comprising the first downlinkcarrier. The same concept may apply to, for example, carrier activation.When the specification indicates that a first carrier is activated, itequally means that the cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in wireless device, base station, radio environment, network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, theexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

Example embodiments of the invention may enable wireless device handoverin heterogeneous wireless networks. Other example embodiments maycomprise a non-transitory tangible computer readable media comprisinginstructions executable by one or more processors to cause handover inheterogeneous wireless networks. Yet other example embodiments maycomprise an article of manufacture that comprises a non-transitorytangible computer readable machine-accessible medium having instructionsencoded thereon for enabling programmable hardware to cause a device(e.g. wireless communicator, UE, base station, etc.) to handover inheterogeneous wireless networks. The device may include processors,memory, interfaces, and/or the like. Other example embodiments maycomprise communication networks comprising devices such as basestations, wireless devices (or user equipment: UE), servers, switches,antennas, and/or the like.

FIG. 6 depicts message flows between a base station and a wirelessdevice as per an aspect of an embodiment of the present invention.According to some of the various aspects of embodiments, a first basestation 602 may transmit at least one control message 604 to a wirelessdevice 601. The first base station 602 is one of a plurality of basestations in a wireless network. The wireless device 601 may have oneconnection with the first base station 602. The connection may beconfigurable to carry a plurality of calls over the connection via asingle radio technology. Each call may be from a call category in aplurality of call categories. In an example embodiment, an establishedradio bearer may be considered as a call. For example, an RRC connectionmay be established between the wireless device 601 and a base station602. The wireless device may communicate with the base station via afirst radio bearer for voice call, and a second radio bearer for a datacall (such as web browsing, email, and/or the like). The at least onecontrol message 604 may be configured to cause the configuration ofmeasurement parameters on the wireless device. The at least one controlmessage 604 may be configured to cause triggering measurements of signalquality of a plurality of carriers. The first base station 602 mayreceive at least one measurement report 605 from the wireless device601. The at least one measurement report 605 may comprise signal qualityinformation of a subset of the plurality of carriers.

According to some of the various aspects of embodiments, the first basestation 602 may initiate the handover process by transmitting a firstcontrol message 606 to an MME 603 (via S1 interface) or by transmittinga first control message 606 to a second base station 610 (via X2interface). In an example embodiment, the first base station 602 maytransmit a first control message 606 (via S1 interface) to an MME 603 inthe wireless network to initiate a handover to a second base station. Inanother example embodiment, the first base station 602 may transmit afirst control message to the second base station 610 to initiate thehandover. The first base station 602 may transmit the first controlmessage, if at least one of the following conditions is satisfied: afirst condition, a second condition, and a third condition. If one ofthe first, second or third condition is satisfied, the first basestation 602 may initiate the handover process. The first condition maycomprise: a) the first base station is a first base station type and thesecond base station is a second base station type; b) the signal qualityinformation in the at least one measurement report meets a firstcriterion; and c) the wireless device is in an active call from a firstcall category employing the one connection. The second condition maycomprise: a) the first base station is a first base station type and thesecond base station is a second base station type; b) the signal qualityinformation in the at least one measurement report meets a secondcriterion; and c) the wireless device is not in an active call from thefirst call category employing the one connection. The third conditionmay comprise: a) the first base station and the second base station arethe first base station type; and b) the signal quality information inthe at least one measurement report meets a third criterion. Thehandover triggering process in example embodiments, depends on theestablished call category(ies) if the handover is between base stationsof different types (handover in heterogeneous network). The handovercriterion for handover between base stations of the first type or basestations of the second type may not depend on the call category. Inexample embodiments, handover for delay sensitive application may becontrolled according to a different criteria in heterogeneous networks.Handover between base stations in different layers in a heterogeneousnetwork may experience higher delay. Handover of delay sensitivecommunications may be controlled to reduce the possibility of handover.This may improve overall call quality.

According to some of the various aspects of embodiments, if the firstcontrol message 606 is transmitted to an MME 603, the first base station602 may receive a second control message 607 from the MME 603. If thefirst control message 606 was transmitted to the second base station610, the first base station 602 may receive a second control message 607from the second base station 610. The second control message 607 mayindicate that the second base station accepted the handover request. Thefirst base station 602 may transmit a handover command to the wirelessdevice 601. The handover command may initiate a handover process in thewireless device 601. The first base station type and the second basestation type may have substantially different transmit powers. The firstcriterion may be different from the second criterion. In an exampleembodiment, the second criterion may be configured so that the firstbase station may not initiate a handover. The call may be dropped andthe wireless device may establish a connection with the second basestation.

A call may be carried over a radio bearer. The at least one measurementreport may comprise: at least one channel state information reportand/or at least one RRC measurement report. The wireless device mayperiodically transmit channel state information reports to the basestation, when the wireless device is in RRC connected mode. The wirelessdevice may transmit RRC measurement reports, if measurement parametersare configured by RRC connection configuration message(s). In an exampleembodiment, the first base station type may be a macro base station, andthe second base station type may be a femto base station. In an exampleembodiment, the single radio technology may be LTE or LTE-AdvancedTechnology. The one connection may be an RRC connection. The wirelessdevice may be configurable to maintain only one connection at a timewith the first base station. The second base station may comprise atleast one carrier in the subset of the plurality of carriers. The firstcall category may be a voice service, for example a voice serviceoffered by a service provider. The first call category may be a delaysensitive service, for example a delay sensitive service offered by aservice provider.

According to some of the various aspects of embodiments, a first basestation may initiate handover of a wireless device in connected modefrom the first base station to a second base station. The first basestation and the second base station may have substantially differenttransmit powers. FIG. 6 depicts message flows between a base station602, MME 603 and a wireless device 601 as per an aspect of an embodimentof the present invention. The base station 602 may transmit at least onecontrol message 604 to the wireless device 601. The at least one controlmessage may configure measurement parameters of the wireless device. Theat least one control message 604 may be configured to cause triggeringmeasurements of signal quality of a plurality of carriers.

The first base station 602 may receive at least one measurement report605 from the wireless device 601. The at least one measurement report605 may comprise signal quality information of a subset of the pluralityof carriers. The base station 602 may transmit a first control message606 to an MME 603 (or the second base station 610) in the network, ifthe signal quality information in the at least one measurement reportmeets a first criterion and the wireless device is in an active callfrom a first call category with the first base station. The base station602 may transmit a first control message 606 to an MME 603 (or thesecond base station 610) in the network, if the signal qualityinformation meets a second criterion and the wireless device is not inan active call from the first call category with the first base station.The base station 602 may receive a second control message 607 from theMME 603 (or from the second base station 610). The second controlmessage 607 may indicate that the second base station accepted thehandover request. The base station 602 may transmit a handover command608 to the wireless device. The handover command may initiate thehandover process in the wireless device. The first criterion may bedifferent than the second criterion.

The first call category may be a voice service or a delay sensitiveservice offered by a service provider. The first base station may be amacro base station, a femto base station, pico base station, or a closedsubscriber group base station. The second base station may be a macrobase station, a femto base station, pico base station, or a closedsubscriber group base station.

The first criterion and the second criterion may consider a relativesignal quality value. The relative signal quality value may consider afirst signal quality value of a carrier of the first base station and asecond signal quality value of a carrier of the second base station. Thefirst criterion may employ comparison of the relative signal qualityvalue with a first threshold value, and the second criterion may employcomparison of the relative signal quality value with a second thresholdvalue. The second signal quality value may consider a measured signalquality value and a bias value. The first criterion may employ a firstbias value for computing the second signal quality value. The secondcriterion may employ a second bias value for computing the second signalquality value. The first bias value may be smaller than the second biasvalue.

The wireless device may spend a longer period of connection time withthe first base station before being handed over to the second basestation if the wireless device is in an active call from the first callcategory with the first base station. The first criterion may consideran absolute signal quality value. The second criterion may consider anabsolute signal quality value. The user of the wireless device may bebilled differently for calls from the first call category that arecarried through the first base station and the second base station. Thewireless device may be in an active call from a second call categorywith the first base station. The first call category and the second callcategory may be different. Initiating a handover using the firstcriterion may depend on whether the wireless device is in an active callfrom a first call category with the first base station. Initiating ahandover using the first criterion may not depend on whether thewireless device is or is not in an active call from a second callcategory with the first base station. The second call category may be anon-delay-sensitive service.

The first base station may receive a proximity indication message fromthe wireless device before transmitting the at least one controlmessage. The proximity indication message may indicate that the wirelessdevice entered the proximity of the second base station. The proximityindication may be received, if the CSG ID (closed subscriber groupidentifier) of the second base station is in the CSG white-list of thewireless device. The proximity indication may comprise the carrierfrequency of the second base station or the radio access technology ofthe second base station. The purpose of this procedure may be toindicate that the wireless device is entering or leaving the proximityof one or more cells whose CSG IDs are in the UEs CSG white-list. Thedetection of proximity may be based on an autonomous search function.The process may be initiated, if the wireless device enters or leavesthe proximity of one or more cell(s), whose CSG IDs are in the wirelessdevice CSG white-list, on an LTE or UMTS frequency while proximityindication is enabled for such cells.

The base station may transmit an RRC reconfiguration message to thewireless device configuring proximity indication in the wireless device.The at least one control message may comprise at least one carrierfrequency, at least one measurement object, and/or at least onereporting event criterion. The at least one measurement report maycomprise at least a physical cell ID of a carrier of the second basestation, and/or a signal quality measurement result.

The first base station may transmit an RRC reconfiguration message tothe wireless device after receiving the at least one measurement report.The RRC reconfiguration message may request for system information ofthe second base station. The RRC reconfiguration message may comprisethe physical cell ID of the second base station. The base station mayreceive a measurement report from the wireless device comprising CGI(cell global identifier), TAI (tracking area identifier), CSG ID (cellsubscriber group Identifier) or member indication, or any combination ofthese parameters. The first control message may comprise the second basestation CGI and/or CSG ID.

The first control message may comprise Cell Access Mode of the secondbase station, if the second base station is a hybrid cell. The MME(mobility management entity) performs access control to determine if thehandover is accepted or rejected. The handover command comprisesmobility control information.

According to some of the various aspects of embodiments, a first basestation may handover a wireless device in connected mode from the firstbase station to a second base station in the plurality of base stations.The first base station and the second base station may havesubstantially different transmit powers. The base station may initiate ahandover using a first criterion, if the wireless device is in an activecall from a first call category with the first base station. The basestation may initiate a handover using a second criterion, if thewireless device is not in an active call from the first call categorywith the first base station.

According to some of the various aspects of embodiments, a first basestation may handover a wireless device in connected mode from the firstbase station to a second base station in the plurality of base stations.The first base station may transmit at least one control message to thewireless device. The at least one control message may configuremeasurement parameters of the wireless device. The measurementconfiguration may trigger measurements of signal quality of a pluralityof carriers. The base station may receive at least one measurementreport from the wireless device in response to the at least one controlmessage. The first base station may receive at least one measurementreport from the wireless device. The at least one measurement report maycomprise signal quality information of a subset of the plurality ofcarriers. The base station may transmit a first control message to anMME (or the second base station) in the network, if the signal qualityof the second base station meets a first criterion, when the wirelessdevice is in an active call from a first call category with the firstbase station. The base station may transmit a first control message toan MME (or the second base station) in the network, if the signalquality of the second base station meets a second criterion, when thewireless device is not in an active call from the first call categorywith the first base station. The base station may receive a secondcontrol message from the MME. The second control message may indicatethat the second base station accepted the handover request. The basestation may transmit a handover command to the wireless device. Thehandover command may initiate the handover process in the wirelessdevice.

According to some of the various aspects of embodiments, a first basestation may handover a wireless device in connected mode from the firstbase station to a second base station in the plurality of base stations.The base station may initiate a handover employing a second criterion,if the wireless device is not in an active call from a first callcategory with the first base station. The base station may not initiatea handover to the second base station, if the wireless device is in anactive call from the first call category with the first base station.

According to some of the various aspects of embodiments, a first basestation may handover a wireless device in connected mode from the firstbase station to a second base station. The first base station maytransmit at least one control message to the wireless device, the atleast one control message may configure measurement parameters of thewireless device. The measurement configuration may trigger measurementsof signal quality of a plurality of carriers. The base station mayreceive at least one measurement report from the wireless device inresponse to the at least one control message. The at least onemeasurement report may comprise signal quality information of a subsetof the plurality of carriers. If the wireless device is not in an activecall from a first call category with the first base station, and thesignal quality of the second base station meets a second criterion, thebase station may: a) transmit a first control message to an MME in thenetwork, b) receive a second control message from the MME, the secondcontrol message indicating that the second base station accepted thehandover request, and/or c) transmit a handover command to the wirelessdevice. The handover command may initiate the handover process in thewireless device. If the wireless device is in an active call from thefirst call category with the first base station, base station may notinitiate a handover to the second base station.

FIG. 7 depicts wireless device 601 handover between a first base station602 with coverage area 704 and a second base station 610 with coveragearea 705 as per an aspect of an embodiment of the present invention. Thearrow 706 shows an example trajectory of the wireless device 601. Thefirst criterion and the second criterion employed for handover aresubstantially different criteria. The handover from a macro-cell to apico/femto cell may take a substantially longer handover completionperiod than the handover between two macro-cells or twopico/femto-cells. Calls from the first category may be delay sensitiveand a relatively long handover delay may negatively impact the callquality, or may cause interruption in the call, or may cause the call todrop. If the first criterion is employed for handover initiation, thehandover decision to a pico/femto cell may be delayed as much aspossible, and the first base station may possibly prevent a handoverfrom happening (compared with the case when the wireless device employsthe first criterion). In another implementation option, the network maynot initiate a handover if the wireless device is an active firstcategory call, because a handover may negatively impact the quality ofthe call. The network may wait until the first category call isterminated, and then initiate a handover, for example employing thesecond criterion. The service operators billing practices may bedifferent in macro cells compared with some femto/pico cells. Forexample, a service operator may bill at a lower rate when a call isconnected to a home femto cell that uses a subscriber provided backhaul,rather than service provider backhaul. In such a scenario, it may beadvantageous for the service operators to keep the first category callas long as possible on the macro cell, so the subscriber is potentiallybilled a higher amount. For many reasons not limited to the abovereasons, the service operators may choose to employ two differenthandover criterions depending on what call categories are active in thewireless device. The handover decision may depend on whether a firstcall category is active or not, and may be independent of presence orlack of presence of a second call category, wherein the first callcategory and the second call category are different. For example thefirst call category may be the service operators provided voice call,and the second call category may be a data session.

While the wireless device is in RRC-connected state, the wireless devicemay perform measurement and mobility procedures based on theconfiguration provided by the network. The wireless device may notsupport manual selection of CSG IDs while in RRC-connected state.Handover to a base station follows the framework ofwireless-device-assisted and network-controlled handover. Handover to afemto or pico base station may be different from the normal handoverprocedure in different aspects.

In case the wireless device is able to determine, using autonomoussearch procedures, that it is near a CSG or hybrid cell whose CSG ID isin the wireless device's CSG white-list, the wireless device may provideto the source base station an indication of proximity. The proximityindication may be employed as follows: a) if a measurement configurationis not present for the concerned frequency/RAT (radio accesstechnology), the source base station may configure the wireless deviceto perform measurements and reporting for the concerned frequency/RAT;b) the source base station may determine whether to perform otheractions related to handover to base stations based on having received aproximity indication (for example, the source base station may notconfigure the wireless device to acquire system information of the basestation unless it has received a proximity indication).

Due to the typical cell size of a pico/femto base stations being muchsmaller than macro cells, there can be multiple pico/femto base stationswithin the coverage of the source base station that have the samePSC/PCI (physical scrambling code/physical cell identifier). This leadsto a condition referred to as PSC/PCI confusion, wherein the source basestation is unable to determine the correct target cell for handover fromthe PSC/PCI included in the measurement reports from the wirelessdevice. PSC/PCI confusion may be solved by the wireless device reportingthe global cell identity of the target pico/femto base station. If thetarget cell is a hybrid cell, prioritization of allocated resources maybe performed based on the wireless device's membership status. Accesscontrol may be done by a two step process, where first the wirelessdevice reports the membership status based on the CSG ID received fromthe target cell and the wireless device's CSG white-list, and then thenetwork verifies the reported status. A hybrid cell is a CSG cell thatalso accepts connections from non-member wireless devices. Hybrid Cellsmay have a CSG Indication bit set to FALSE but broadcast a CSG Identity.The PCI values for hybrid cells may not be contained within the reservedPCI range for CSG cells. Similar to CSG cells, the network may reserve aPCI list for hybrid cells.

According to some of the various aspects of embodiments, in an LTE orLTE-advanced network, mobility from base station to a base station'sCSG/hybrid cell may take place with the S1 handover procedure or X2handover procedure. In the following call flow the source cell can be apico/femto base station or a base station. The procedure may apply toany scenario where the CSG ID is provided by the wireless device orprovided by the source base station. Some of the following tasks in thecall flow may be not executed, and some of the steps may be eliminatedwithout affecting the handover performance depending on the deploymentscenario. 1) The source base station may configure the wireless devicewith proximity indication control. 2) The wireless device may send an“entering” proximity indication when it determines it may be near a cell(based on autonomous search procedures) whose CSG ID is in the wirelessdevice's CSG white-list. The proximity indication may include the RATand frequency of the cell. 3) If a measurement configuration is notpresent for the concerned frequency/RAT, the source base station mayconfigure the wireless device with relevant measurement configurationincluding measurement gaps as needed, so that the wireless device mayperform measurements on the reported RAT and frequency. The network mayalso use the proximity indication to minimize the requesting of handoverpreparation information of CSG/hybrid cells by avoiding requesting suchinformation when the wireless device is not in the geographical areawhere cells whose CSG IDs are in the wireless devices CSG White-list arelocated. 4) The wireless device may send a measurement report includingthe PCI (physical cell Identifier). 5) The source base station mayconfigure the wireless device to perform SI (system information)acquisition and reporting of a particular PCI. 6) The wireless devicemay perform SI acquisition using autonomous gaps, for example, thewireless device may suspend reception and transmission with the sourcebase station within the limits defined in to acquire the relevant systeminformation from the target base station. 7) The wireless device maysend a measurement report including CGI (cell global ID), TAI (trackingarea identifier), CSG ID (cell subscriber group identifier) andmember/non-member indication. 8) The source base station may include thetarget CGI and the CSG ID in the Handover Required message sent to theMME. If the target is a hybrid cell, the Cell Access Mode of the targetmay be included. 9) The MME may perform wireless device access controlto the CSG cell based on the CSG ID received in the Handover Requiredmessage and the stored CSG subscription data for the wireless device. Ifthe access control procedure fails, the MME may end the handoverprocedure by replying with the Handover Preparation Failure message. Ifthe Cell Access Mode is present, the MME may determine the CSGMembership Status of the wireless device handing over to the hybrid celland includes it in the Handover Request message. 10) The MME (mobilitymanagement entity) may send the Handover Request message to the targetbase station including the target CSG ID received in the HandoverRequired message. If the target is a hybrid cell the CSG MembershipStatus may be included in the Handover Request message. 11) The targetbase station may verify that the CSG ID received in the Handover Requestmessage matches the CSG ID broadcast in the target cell and if suchvalidation is successful it may allocate appropriate resources. Wirelessdevice prioritization may also be applied if the CSG Membership Statusindicates that the wireless device is a member. 12) The target basestation may send the Handover Request Acknowledge message to the MME viathe base station GW if present. 13) The MME sends the Handover Commandmessage to the source base station. 14) The source base station maytransmit the Handover Command (RRC Connection Reconfiguration messageincluding mobility control information) to the wireless device.

After sending an “entering” proximity indication (step 2), if thewireless device determines that it is no longer near a cell whose CSG IDis in the wireless device's CSG white-list, the wireless device may senda “leaving” proximity indication to the source base station. Uponreception of this indication, the source base station may reconfigurethe wireless device to stop measurements on the reported RAT andfrequency. In the above procedure, steps 2 and 3 may not be performed incase the wireless device has not previously visited the base station,e.g., when the wireless device first visits a hybrid cell. The PCI(physical cell identifier) confusion may be resolved by steps 5, 6 and7. The source base station may request SI acquisition and reporting forany PCI, not limited to PCIs of CSG or hybrid cells.

In an example embodiment of the invention the wireless device mayimplement the following measurement model. Assume that point A is themeasurements (samples) depending on an internal physical layerimplementations. Internal layer 1 filtering may be performed on theinputs measured at point A. Exact filtering is implementation dependent.How the measurements are actually executed in the physical layer by animplementation (inputs A and Layer 1 filtering) may not be constrainedby the standard. A measurement reported by layer 1 enters to layer 3filtering at point B after layer 1 filtering. Layer 3 filtering may beperformed on the measurements provided at point B. The behavior of theLayer 3 filters may be standardized and the configuration of the layer 3filters may be provided by RRC signaling. Filtering reporting period atLayer 3 filtering (at point C) equals one measurement period at B. Ameasurement report may be available after processing in the layer 3filter. The reporting rate is identical to the reporting rate at pointB. This measurement may be used as input for one or more evaluation ofreporting criteria. Evaluation of reporting criteria may check whetheractual measurement reporting is necessary. The evaluation may employmore than one flow of measurements at reference point C e.g. to comparebetween different measurements. The wireless device may evaluate thereporting criteria at least every time a new measurement result isreported. The reporting criteria may be standardized and theconfiguration may be provided by RRC signaling (wireless devicemeasurements). Then measurement report information (message) may be senton the radio interface. Layer 1 filtering may introduce a certain levelof measurement averaging. How and when the wireless device performs therequired measurements may be implementation specific to the point thatthe output at B fulfills the performance requirements. Layer 3 filteringand parameters may not introduce any delay in the sample availabilitybetween B and C.

The wireless device reports measurement information in accordance withthe measurement configuration as provided by network. Network mayprovide the measurement configuration applicable for a wireless devicein RRC-connected by means of dedicated signaling, for example, using theRRC Connection Reconfiguration message. The wireless device may berequested to perform the following types of measurements: a)Intra-frequency measurements: measurements at the downlink carrierfrequency(ies) of the serving cell(s), b) Inter-frequency measurements:measurements at frequencies that differ from any of the downlink carrierfrequency(ies) of the serving cell(s), c) Inter-RAT measurements of UTRAfrequencies, d) Inter-RAT measurements.

The measurement configuration may include the following parameters:

Measurement objects: The objects on which the wireless device mayperform the measurements. For intra-frequency and inter-frequencymeasurements a measurement object may be a single network carrierfrequency. Associated with this carrier frequency, network may configurea list of cell specific offsets and a list of blacklisted cells.Blacklisted cells may not be considered in event evaluation ormeasurement reporting. For inter-RAT UMTS measurements a measurementobject may be a set of cells on a single UMTS carrier frequency. Somemeasurements using the above mentioned measurement objects, may concerna single cell, e.g. measurements used to report neighboring cell systeminformation, PCell wireless device Rx-Tx time difference.

Reporting configurations: A list of reporting configurations where eachreporting configuration may include the following: a) The reportingcriterion that triggers the wireless device to send a measurementreport. This may either be periodical or a single event description. B)The quantities that the wireless device includes in the measurementreport and associated information (e.g. number of cells to report).

Measurement identities: A list of measurement identities where eachmeasurement identity links one measurement object with one reportingconfiguration. By configuring multiple measurement identities it ispossible to link more than one measurement object to the same reportingconfiguration, as well as to link more than one reporting configurationto the same measurement object. The measurement identity is used as areference number in the measurement report.

Quantity configurations: One quantity configuration may be configuredper RAT type. The quantity configuration may define the measurementquantities and associated filtering used for all event evaluation andrelated reporting of that measurement type. One filter may be configuredper measurement quantity.

Measurement gaps: Periods that the wireless device may use to performmeasurements, for example, no (UL, DL) transmissions are scheduled.

Network may configure a single measurement object for a given frequency.Network may configure multiple instances of the same event e.g. byconfiguring two reporting configurations with different thresholds. Thewireless device may maintain a single measurement object list, areporting configuration list, and a measurement identities list. Themeasurement object list may include measurement objects, that arespecified per RAT type, possibly including intra-frequency object(s)(for example, the object(s) corresponding to the servingfrequency(ies)), inter-frequency object(s) and inter-RAT objects.Similarly, the reporting configuration list may include network andinter-RAT reporting configurations. Any measurement object may be linkedto any reporting configuration of the same RAT type. Some reportingconfigurations may not be linked to a measurement object. Likewise, somemeasurement objects may not be linked to a reporting configuration.

The measurement procedures may distinguish the following types of cells:a) The serving cell(s): these are the PCell and one or more SCells, ifconfigured for a wireless device supporting CA (carrier aggregation), b)Listed cells: these are cells listed within the measurement object(s),or c) Detected cells: these are cells that are not listed within themeasurement object(s) but are detected by the wireless device on thecarrier frequency(ies) indicated by the measurement object(s). Fornetwork, the wireless device measures and reports on the servingcell(s), listed cells and detected cells. This specification is based onthe assumption that typically CSG cells of home deployment type may notbe indicated within the neighbor list. Furthermore, the assumption isthat for non-home deployments, the physical cell identity is uniquewithin the area of a large macro cell (for example, as for UTRAN).

Measurement reports may be triggered when one of the followingconditions are met:

Event A1 (serving becomes better than threshold): for this measurement,the primary or secondary cell that is configured on the frequencyindicated in the associated measurement object may be considered to bethe serving cell.

Event A2 (serving becomes worse than threshold): for this measurement,the primary or secondary cell that is configured on the frequencyindicated in the associated measurement object may be considered to bethe serving cell.

Event A3 (neighbor becomes offset better than PCell): The cell(s) thattriggers the event may be on the frequency indicated in the associatedmeasurement object which may be different from the (primary) frequencyused by the PCell.

Event A4 (neighbor becomes better than threshold).

Event A5 (PCell becomes worse than threshold1 and neighbor becomesbetter than threshold2): The cell(s) that triggers the event is on thefrequency indicated in the associated measurement object which may bedifferent from the (primary) frequency used by the PCell.

Event A6 (neighbor becomes offset better than SCell): for thismeasurement, the (secondary) cell that is configured on the frequencyindicated in the associated measurement object may be considered to bethe serving cell. The neighbor(s) may be on the same frequency as theSCell, for example, both may be on the frequency indicated in theassociated measurement object.

Event B1 (Inter RAT neighbor becomes better than threshold): for UMTSand CDMA2000, trigger the event for cells may be included in thecorresponding measurement object.

Event B2 (PCell becomes worse than threshold1 and inter RAT neighbourbecomes better than threshold2). For UTRA and CDMA2000, the event may betriggered for cells included in the corresponding measurement object.

According to some of the various aspects of embodiments, the packets inthe downlink may be transmitted via downlink physical channels. Thecarrying packets in the uplink may be transmitted via uplink physicalchannels. The baseband data representing a downlink physical channel maybe defined in terms of at least one of the following actions: scramblingof coded bits in codewords to be transmitted on a physical channel;modulation of scrambled bits to generate complex-valued modulationsymbols; mapping of the complex-valued modulation symbols onto one orseveral transmission layers; precoding of the complex-valued modulationsymbols on layer(s) for transmission on the antenna port(s); mapping ofcomplex-valued modulation symbols for antenna port(s) to resourceelements; and/or generation of complex-valued time-domain OFDM signal(s)for antenna port(s).

Codeword, transmitted on the physical channel in one subframe, may bescrambled prior to modulation, resulting in a block of scrambled bits.The scrambling sequence generator may be initialized at the start ofsubframe(s). Codeword(s) may be modulated using QPSK, 16QAM, 64QAM,128QAM, and/or the like resulting in a block of complex-valuedmodulation symbols. The complex-valued modulation symbols for codewordsto be transmitted may be mapped onto one or several layers. Fortransmission on a single antenna port, a single layer may be used. Forspatial multiplexing, the number of layers may be less than or equal tothe number of antenna port(s) used for transmission of the physicalchannel. The case of a single codeword mapped to multiple layers may beapplicable when the number of cell-specific reference signals is four orwhen the number of UE-specific reference signals is two or larger. Fortransmit diversity, there may be one codeword and the number of layersmay be equal to the number of antenna port(s) used for transmission ofthe physical channel.

The precoder may receive a block of vectors from the layer mapping andgenerate a block of vectors to be mapped onto resources on the antennaport(s). Precoding for spatial multiplexing using antenna port(s) withcell-specific reference signals may be used in combination with layermapping for spatial multiplexing. Spatial multiplexing may support twoor four antenna ports and the set of antenna ports used may be {0,1} or{0, 1, 2, 3}. Precoding for transmit diversity may be used incombination with layer mapping for transmit diversity. The precodingoperation for transmit diversity may be defined for two and four antennaports. Precoding for spatial multiplexing using antenna ports withUE-specific reference signals may also, for example, be used incombination with layer mapping for spatial multiplexing. Spatialmultiplexing using antenna ports with UE-specific reference signals maysupport up to eight antenna ports. Reference signals may be pre-definedsignals that may be used by the receiver for decoding the receivedphysical signal, estimating the channel state, and/or other purposes.

For antenna port(s) used for transmission of the physical channel, theblock of complex-valued symbols may be mapped in sequence to resourceelements. In resource blocks in which UE-specific reference signals arenot transmitted the PDSCH may be transmitted on the same set of antennaports as the physical broadcast channel in the downlink (PBCH). Inresource blocks in which UE-specific reference signals are transmitted,the PDSCH may be transmitted, for example, on antenna port(s) {5, {7},{8}, or {7, 8, . . . , v+6}, where v is the number of layers used fortransmission of the PDSCH.

Common reference signal(s) may be transmitted in physical antennaport(s). Common reference signal(s) may be cell-specific referencesignal(s) (RS) used for demodulation and/or measurement purposes.Channel estimation accuracy using common reference signal(s) may bereasonable for demodulation (high RS density). Common referencesignal(s) may be defined for LTE technologies, LTE-advancedtechnologies, and/or the like. Demodulation reference signal(s) may betransmitted in virtual antenna port(s) (i.e., layer or stream). Channelestimation accuracy using demodulation reference signal(s) may bereasonable within allocated time/frequency resources. Demodulationreference signal(s) may be defined for LTE-advanced technology and maynot be applicable to LTE technology. Measurement reference signal(s),may also called CSI (channel state information) reference signal(s), maybe transmitted in physical antenna port(s) or virtualized antennaport(s). Measurement reference signal(s) may be Cell-specific RS usedfor measurement purposes. Channel estimation accuracy may be relativelylower than demodulation RS. CSI reference signal(s) may be defined forLTE-advanced technology and may not be applicable to LTE technology.

In at least one of the various embodiments, uplink physical channel(s)may correspond to a set of resource elements carrying informationoriginating from higher layers. The following example uplink physicalchannel(s) may be defined for uplink: a) Physical Uplink Shared Channel(PUSCH), b) Physical Uplink Control Channel (PUCCH), c) Physical RandomAccess Channel (PRACH), and/or the like. Uplink physical signal(s) maybe used by the physical layer and may not carry information originatingfrom higher layers. For example, reference signal(s) may be consideredas uplink physical signal(s). Transmitted signal(s) in slot(s) may bedescribed by one or several resource grids including, for example,subcarriers and SC-FDMA or OFDMA symbols. Antenna port(s) may be definedsuch that the channel over which symbol(s) on antenna port(s) may beconveyed and/or inferred from the channel over which other symbol(s) onthe same antenna port(s) is/are conveyed. There may be one resource gridper antenna port. The antenna port(s) used for transmission of physicalchannel(s) or signal(s) may depend on the number of antenna port(s)configured for the physical channel(s) or signal(s).

Element(s) in a resource grid may be called a resource element. Aphysical resource block may be defined as N consecutive SC-FDMA symbolsin the time domain and/or M consecutive subcarriers in the frequencydomain, wherein M and N may be pre-defined integer values. Physicalresource block(s) in uplink(s) may comprise of M×N resource elements.For example, a physical resource block may correspond to one slot in thetime domain and 180 kHz in the frequency domain. Baseband signal(s)representing the physical uplink shared channel may be defined in termsof: a) scrambling, b) modulation of scrambled bits to generatecomplex-valued symbols, c) mapping of complex-valued modulation symbolsonto one or several transmission layers, d) transform precoding togenerate complex-valued symbols, e) precoding of complex-valued symbols,f) mapping of precoded complex-valued symbols to resource elements, g)generation of complex-valued time-domain SC-FDMA signal(s) for antennaport(s), and/or the like.

For codeword(s), block(s) of bits may be scrambled with UE-specificscrambling sequence(s) prior to modulation, resulting in block(s) ofscrambled bits. Complex-valued modulation symbols for codeword(s) to betransmitted may be mapped onto one, two, or more layers. For spatialmultiplexing, layer mapping(s) may be performed according to pre-definedformula(s). The number of layers may be less than or equal to the numberof antenna port(s) used for transmission of physical uplink sharedchannel(s). The example of a single codeword mapped to multiple layersmay be applicable when the number of antenna port(s) used for PUSCH is,for example, four. For layer(s), the block of complex-valued symbols maybe divided into multiple sets, each corresponding to one SC-FDMA symbol.Transform precoding may be applied. For antenna port(s) used fortransmission of the PUSCH in a subframe, block(s) of complex-valuedsymbols may be multiplied with an amplitude scaling factor in order toconform to a required transmit power, and mapped in sequence to physicalresource block(s) on antenna port(s) and assigned for transmission ofPUSCH.

According to some of the various embodiments, data may arrive to thecoding unit in the form of two transport blocks every transmission timeinterval (TTI) per UL cell. The following coding actions may beidentified for transport block(s) of an uplink carrier: a) Add CRC tothe transport block, b) Code block segmentation and code block CRCattachment, c) Channel coding of data and control information, d) Ratematching, e) Code block concatenation. f) Multiplexing of data andcontrol information, g) Channel interleaver, h) Error detection may beprovided on UL-SCH (uplink shared channel) transport block(s) through aCyclic Redundancy Check (CRC), and/or the like. Transport block(s) maybe used to calculate CRC parity bits. Code block(s) may be delivered tochannel coding block(s). Code block(s) may be individually turboencoded. Turbo coded block(s) may be delivered to rate matchingblock(s).

Physical uplink control channel(s) (PUCCH) may carry uplink controlinformation. Simultaneous transmission of PUCCH and PUSCH from the sameUE may be supported if enabled by higher layers. For a type 2 framestructure, the PUCCH may not be transmitted in the UpPTS field. PUCCHmay use one resource block in each of the two slots in a subframe.Resources allocated to UE and PUCCH configuration(s) may be transmittedvia control messages. PUCCH may comprise: a) positive and negativeacknowledgements for data packets transmitted at least one downlinkcarrier, b) channel state information for at least one downlink carrier,c) scheduling request, and/or the like.

According to some of the various aspects of embodiments, cell search maybe the procedure by which a wireless device may acquire time andfrequency synchronization with a cell and may detect the physical layerCell ID of that cell (transmitter). An example embodiment forsynchronization signal and cell search is presented below. A cell searchmay support a scalable overall transmission bandwidth corresponding to 6resource blocks and upwards. Primary and secondary synchronizationsignals may be transmitted in the downlink and may facilitate cellsearch. For example, 504 unique physical-layer cell identities may bedefined using synchronization signals. The physical-layer cellidentities may be grouped into 168 unique physical-layer cell-identitygroups, group(s) containing three unique identities. The grouping may besuch that physical-layer cell identit(ies) is part of a physical-layercell-identity group. A physical-layer cell identity may be defined by anumber in the range of 0 to 167, representing the physical-layercell-identity group, and a number in the range of 0 to 2, representingthe physical-layer identity within the physical-layer cell-identitygroup. The synchronization signal may include a primary synchronizationsignal and a secondary synchronization signal.

According to some of the various aspects of embodiments, the sequenceused for a primary synchronization signal may be generated from afrequency-domain Zadoff-Chu sequence according to a pre-defined formula.A Zadoff-Chu root sequence index may also be predefined in aspecification. The mapping of the sequence to resource elements maydepend on a frame structure. The wireless device may not assume that theprimary synchronization signal is transmitted on the same antenna portas any of the downlink reference signals. The wireless device may notassume that any transmission instance of the primary synchronizationsignal is transmitted on the same antenna port, or ports, used for anyother transmission instance of the primary synchronization signal. Thesequence may be mapped to the resource elements according to apredefined formula.

For FDD frame structure, a primary synchronization signal may be mappedto the last OFDM symbol in slots 0 and 10. For TDD frame structure, theprimary synchronization signal may be mapped to the third OFDM symbol insubframes 1 and 6. Some of the resource elements allocated to primary orsecondary synchronization signals may be reserved and not used fortransmission of the primary synchronization signal.

According to some of the various aspects of embodiments, the sequenceused for a secondary synchronization signal may be an interleavedconcatenation of two length-31 binary sequences. The concatenatedsequence may be scrambled with a scrambling sequence given by a primarysynchronization signal. The combination of two length-31 sequencesdefining the secondary synchronization signal may differ betweensubframe 0 and subframe 5 according to predefined formula(s). Themapping of the sequence to resource elements may depend on the framestructure. In a subframe for FDD frame structure and in a half-frame forTDD frame structure, the same antenna port as for the primarysynchronization signal may be used for the secondary synchronizationsignal. The sequence may be mapped to resource elements according to apredefined formula.

Example embodiments for the physical channels configuration will now bepresented. Other examples may also be possible. A physical broadcastchannel may be scrambled with a cell-specific sequence prior tomodulation, resulting in a block of scrambled bits. PBCH may bemodulated using QPSK, and/or the like. The block of complex-valuedsymbols for antenna port(s) may be transmitted during consecutive radioframes, for example, four consecutive radio frames. In some embodimentsthe PBCH data may arrive to the coding unit in the form of a onetransport block every transmission time interval (TTI) of 40 ms. Thefollowing coding actions may be identified. Add CRC to the transportblock, channel coding, and rate matching. Error detection may beprovided on PBCH transport blocks through a Cyclic Redundancy Check(CRC). The transport block may be used to calculate the CRC parity bits.The parity bits may be computed and attached to the BCH (broadcastchannel) transport block. After the attachment, the CRC bits may bescrambled according to the transmitter transmit antenna configuration.Information bits may be delivered to the channel coding block and theymay be tail biting convolutionally encoded. A tail bitingconvolutionally coded block may be delivered to the rate matching block.The coded block may be rate matched before transmission.

A master information block may be transmitted in PBCH and may includesystem information transmitted on broadcast channel(s). The masterinformation block may include downlink bandwidth, system framenumber(s), and PHICH (physical hybrid-ARQ indicator channel)configuration. Downlink bandwidth may be the transmission bandwidthconfiguration, in terms of resource blocks in a downlink, for example 6may correspond to 6 resource blocks, 15 may correspond to 15 resourceblocks and so on. System frame number(s) may define the N (for exampleN=8) most significant bits of the system frame number. The M (forexample M=2) least significant bits of the SFN may be acquiredimplicitly in the PBCH decoding. For example, timing of a 40 ms PBCH TTImay indicate 2 least significant bits (within 40 ms PBCH TTI, the firstradio frame: 00, the second radio frame: 01, the third radio frame: 10,the last radio frame: 11). One value may apply for other carriers in thesame sector of a base station (the associated functionality is common(e.g. not performed independently for each cell). PHICH configuration(s)may include PHICH duration, which may be normal (e.g. one symbolduration) or extended (e.g. 3 symbol duration).

Physical control format indicator channel(s) (PCFICH) may carryinformation about the number of OFDM symbols used for transmission ofPDCCHs (physical downlink control channel) in a subframe. The set ofOFDM symbols possible to use for PDCCH in a subframe may depend on manyparameters including, for example, downlink carrier bandwidth, in termsof downlink resource blocks. PCFICH transmitted in one subframe may bescrambled with cell-specific sequence(s) prior to modulation, resultingin a block of scrambled bits. A scrambling sequence generator(s) may beinitialized at the start of subframe(s). Block (s) of scrambled bits maybe modulated using QPSK. Block(s) of modulation symbols may be mapped toat least one layer and precoded resulting in a block of vectorsrepresenting the signal for at least one antenna port. Instances ofPCFICH control channel(s) may indicate one of several (e.g. 3) possiblevalues after being decoded. The range of possible values of instance(s)of the first control channel may depend on the first carrier bandwidth.

According to some of the various embodiments, physical downlink controlchannel(s) may carry scheduling assignments and other controlinformation. The number of resource-elements not assigned to PCFICH orPHICH may be assigned to PDCCH. PDCCH may support multiple formats.Multiple PDCCH packets may be transmitted in a subframe. PDCCH may becoded by tail biting convolutionally encoder before transmission. PDCCHbits may be scrambled with a cell-specific sequence prior to modulation,resulting in block(s) of scrambled bits. Scrambling sequencegenerator(s) may be initialized at the start of subframe(s). Block(s) ofscrambled bits may be modulated using QPSK. Block(s) of modulationsymbols may be mapped to at least one layer and precoded resulting in ablock of vectors representing the signal for at least one antenna port.PDCCH may be transmitted on the same set of antenna ports as the PBCH,wherein PBCH is a physical broadcast channel broadcasting at least onebasic system information field.

According to some of the various embodiments, scheduling controlpacket(s) may be transmitted for packet(s) or group(s) of packetstransmitted in downlink shared channel(s). Scheduling control packet(s)may include information about subcarriers used for packettransmission(s). PDCCH may also provide power control commands foruplink channels. OFDM subcarriers that are allocated for transmission ofPDCCH may occupy the bandwidth of downlink carrier(s). PDCCH channel(s)may carry a plurality of downlink control packets in subframe(s). PDCCHmay be transmitted on downlink carrier(s) starting from the first OFDMsymbol of subframe(s), and may occupy up to multiple symbol duration(s)(e.g. 3 or 4).

According to some of the various embodiments, PHICH may carry thehybrid-ARQ (automatic repeat request) ACK/NACK. Multiple PHICHs mappedto the same set of resource elements may constitute a PHICH group, wherePHICHs within the same PHICH group may be separated through differentorthogonal sequences. PHICH resource(s) may be identified by the indexpair (group, sequence), where group(s) may be the PHICH group number(s)and sequence(s) may be the orthogonal sequence index within thegroup(s). For frame structure type 1, the number of PHICH groups maydepend on parameters from higher layers (RRC). For frame structure type2, the number of PHICH groups may vary between downlink subframesaccording to a pre-defined arrangement. Block(s) of bits transmitted onone PHICH in one subframe may be modulated using BPSK or QPSK, resultingin a block(s) of complex-valued modulation symbols. Block(s) ofmodulation symbols may be symbol-wise multiplied with an orthogonalsequence and scrambled, resulting in a sequence of modulation symbols

Other arrangements for PCFICH, PHICH, PDCCH, and/or PDSCH may besupported. The configurations presented here are for example purposes.In another example, resources PCFICH, PHICH, and/or PDCCH radioresources may be transmitted in radio resources including a subset ofsubcarriers and pre-defined time duration in each or some of thesubframes. In an example, PUSCH resource(s) may start from the firstsymbol. In another example embodiment, radio resource configuration(s)for PUSCH, PUCCH, and/or PRACH (physical random access channel) may usea different configuration. For example, channels may be timemultiplexed, or time/frequency multiplexed when mapped to uplink radioresources.

According to some of the various aspects of embodiments, the physicallayer random access preamble may comprise a cyclic prefix of length Tcpand a sequence part of length Tseq. The parameter values may bepre-defined and depend on the frame structure and a random accessconfiguration. In an example embodiment, Tcp may be 0.1 msec, and Tseqmay be 0.9 msec. Higher layers may control the preamble format. Thetransmission of a random access preamble, if triggered by the MAC layer,may be restricted to certain time and frequency resources. The start ofa random access preamble may be aligned with the start of thecorresponding uplink subframe at a wireless device.

According to an example embodiment, random access preambles may begenerated from Zadoff-Chu sequences with a zero correlation zone,generated from one or several root Zadoff-Chu sequences. In anotherexample embodiment, the preambles may also be generated using otherrandom sequences such as Gold sequences. The network may configure theset of preamble sequences a wireless device may be allowed to use.According to some of the various aspects of embodiments, there may be amultitude of preambles (e.g. 64) available in cell(s). From the physicallayer perspective, the physical layer random access procedure mayinclude the transmission of random access preamble(s) and random accessresponse(s). Remaining message(s) may be scheduled for transmission by ahigher layer on the shared data channel and may not be considered partof the physical layer random access procedure. For example, a randomaccess channel may occupy 6 resource blocks in a subframe or set ofconsecutive subframes reserved for random access preamble transmissions.

According to some of the various embodiments, the following actions maybe followed for a physical random access procedure: 1) layer 1 proceduremay be triggered upon request of a preamble transmission by higherlayers; 2) a preamble index, a target preamble received power, acorresponding RA-RNTI (random access-radio network temporary identifier)and/or a PRACH resource may be indicated by higher layers as part of arequest; 3) a preamble transmission power P_PRACH may be determined; 4)a preamble sequence may be selected from the preamble sequence set usingthe preamble index; 5) a single preamble may be transmitted usingselected preamble sequence(s) with transmission power P_PRACH on theindicated PRACH resource; 6) detection of a PDCCH with the indicated RARmay be attempted during a window controlled by higher layers; and/or thelike. If detected, the corresponding downlink shared channel transportblock may be passed to higher layers. The higher layers may parsetransport block(s) and/or indicate an uplink grant to the physicallayer(s).

According to some of the various aspects of embodiments, a random accessprocedure may be initiated by a physical downlink control channel(PDCCH) order and/or by the MAC sublayer in a wireless device. If awireless device receives a PDCCH transmission consistent with a PDCCHorder masked with its radio identifier, the wireless device may initiatea random access procedure. Preamble transmission(s) on physical randomaccess channel(s) (PRACH) may be supported on a first uplink carrier andreception of a PDCCH order may be supported on a first downlink carrier.

Before a wireless device initiates transmission of a random accesspreamble, it may access one or many of the following types ofinformation: a) available set(s) of PRACH resources for the transmissionof a random access preamble; b) group(s) of random access preambles andset(s) of available random access preambles in group(s); c) randomaccess response window size(s); d) power-ramping factor(s); e) maximumnumber(s) of preamble transmission(s); 0 initial preamble power; g)preamble format based offset(s); h) contention resolution timer(s);and/or the like. These parameters may be updated from upper layers ormay be received from the base station before random access procedure(s)may be initiated.

According to some of the various aspects of embodiments, a wirelessdevice may select a random access preamble using available information.The preamble may be signaled by a base station or the preamble may berandomly selected by the wireless device. The wireless device maydetermine the next available subframe containing PRACH permitted byrestrictions given by the base station and the physical layer timingrequirements for TDD or FDD. Subframe timing and the timing oftransmitting the random access preamble may be determined based, atleast in part, on synchronization signals received from the base stationand/or the information received from the base station. The wirelessdevice may proceed to the transmission of the random access preamblewhen it has determined the timing. The random access preamble may betransmitted on a second plurality of subcarriers on the first uplinkcarrier.

According to some of the various aspects of embodiments, once a randomaccess preamble is transmitted, a wireless device may monitor the PDCCHof a first downlink carrier for random access response(s), in a randomaccess response window. There may be a pre-known identifier in PDCCHthat indentifies a random access response. The wireless device may stopmonitoring for random access response(s) after successful reception of arandom access response containing random access preamble identifiersthat matches the transmitted random access preamble and/or a randomaccess response address to a wireless device identifier. A base stationrandom access response may include a time alignment command. Thewireless device may process the received time alignment command and mayadjust its uplink transmission timing according the time alignment valuein the command. For example, in a random access response, a timealignment command may be coded using 11 bits, where an amount of thetime alignment may be based on the value in the command. In an exampleembodiment, when an uplink transmission is required, the base stationmay provide the wireless device a grant for uplink transmission.

If no random access response is received within the random accessresponse window, and/or if none of the received random access responsescontains a random access preamble identifier corresponding to thetransmitted random access preamble, the random access response receptionmay be considered unsuccessful and the wireless device may, based on thebackoff parameter in the wireless device, select a random backoff timeand delay the subsequent random access transmission by the backoff time,and may retransmit another random access preamble.

According to some of the various aspects of embodiments, a wirelessdevice may transmit packets on an uplink carrier. Uplink packettransmission timing may be calculated in the wireless device using thetiming of synchronization signal(s) received in a downlink. Uponreception of a timing alignment command by the wireless device, thewireless device may adjust its uplink transmission timing. The timingalignment command may indicate the change of the uplink timing relativeto the current uplink timing. The uplink transmission timing for anuplink carrier may be determined using time alignment commands and/ordownlink reference signals.

According to some of the various aspects of embodiments, a timealignment command may indicate timing adjustment for transmission ofsignals on uplink carriers. For example, a time alignment command mayuse 6 bits. Adjustment of the uplink timing by a positive or a negativeamount indicates advancing or delaying the uplink transmission timing bya given amount respectively.

For a timing alignment command received on subframe n, the correspondingadjustment of the timing may be applied with some delay, for example, itmay be applied from the beginning of subframe n+6. When the wirelessdevice's uplink transmissions in subframe n and subframe n+1 areoverlapped due to the timing adjustment, the wireless device maytransmit complete subframe n and may not transmit the overlapped part ofsubframe n+1.

According to some of the various aspects of embodiments, a wirelessdevice may include a configurable timer (timeAlignmentTimer) that may beused to control how long the wireless device is considered uplink timealigned. When a timing alignment command MAC control element isreceived, the wireless device may apply the timing alignment command andstart or restart timeAlignmentTimer. The wireless device may not performany uplink transmission except the random access preamble transmissionwhen timeAlignmentTimer is not running or when it exceeds its limit. Thetime alignment command may substantially align frame and subframereception timing of a first uplink carrier and at least one additionaluplink carrier. According to some of the various aspects of embodiments,the time alignment command value range employed during a random accessprocess may be substantially larger than the time alignment commandvalue range during active data transmission. In an example embodiment,uplink transmission timing may be maintained on a per time alignmentgroup (TAG) basis. Carrier(s) may be grouped in TAGs, and TAG(s) mayhave their own downlink timing reference, time alignment timer, and/ortime alignment commands. Group(s) may have their own random accessprocess. Time alignment commands may be directed to a time alignmentgroup. The TAG, including the primary cell may be called a primary TAG(pTAG) and the TAG not including the primary cell may be called asecondary TAG (sTAG).

According to some of the various aspects of embodiments, controlmessage(s) or control packet(s) may be scheduled for transmission in aphysical downlink shared channel (PDSCH) and/or physical uplink sharedchannel PUSCH. PDSCH and PUSCH may carry control and datamessage(s)/packet(s). Control message(s) and/or packet(s) may beprocessed before transmission. For example, the control message(s)and/or packet(s) may be fragmented or multiplexed before transmission. Acontrol message in an upper layer may be processed as a data packet inthe MAC or physical layer. For example, system information block(s) aswell as data traffic may be scheduled for transmission in PDSCH. Datapacket(s) may be encrypted packets.

According to some of the various aspects of embodiments, data packet(s)may be encrypted before transmission to secure packet(s) from unwantedreceiver(s). Desired recipient(s) may be able to decrypt the packet(s).A first plurality of data packet(s) and/or a second plurality of datapacket(s) may be encrypted using an encryption key and at least oneparameter that may change substantially rapidly over time. Theencryption mechanism may provide a transmission that may not be easilyeavesdropped by unwanted receivers. The encryption mechanism may includeadditional parameter(s) in an encryption module that changessubstantially rapidly in time to enhance the security mechanism. Examplevarying parameter(s) may comprise various types of system counter(s),such as system frame number. Substantially rapidly may for example implychanging on a per subframe, frame, or group of subframes basis.Encryption may be provided by a PDCP layer between the transmitter andreceiver, and/or may be provided by the application layer. Additionaloverhead added to packet(s) by lower layers such as RLC, MAC, and/orPhysical layer may not be encrypted before transmission. In thereceiver, the plurality of encrypted data packet(s) may be decryptedusing a first decryption key and at least one first parameter. Theplurality of data packet(s) may be decrypted using an additionalparameter that changes substantially rapidly over time.

According to some of the various aspects of embodiments, a wirelessdevice may be preconfigured with one or more carriers. When the wirelessdevice is configured with more than one carrier, the base station and/orwireless device may activate and/or deactivate the configured carriers.One of the carriers (the primary carrier) may always be activated. Othercarriers may be deactivated by default and/or may be activated by a basestation when needed. A base station may activate and deactivate carriersby sending an activation/deactivation MAC control element. Furthermore,the UE may maintain a carrier deactivation timer per configured carrierand deactivate the associated carrier upon its expiry. The same initialtimer value may apply to instance(s) of the carrier deactivation timer.The initial value of the timer may be configured by a network. Theconfigured carriers (unless the primary carrier) may be initiallydeactivated upon addition and after a handover.

According to some of the various aspects of embodiments, if a wirelessdevice receives an activation/deactivation MAC control elementactivating the carrier, the wireless device may activate the carrier,and/or may apply normal carrier operation including: sounding referencesignal transmissions on the carrier, CQI (channel qualityindicator)/PMI(precoding matrix indicator)/RI(ranking indicator)reporting for the carrier, PDCCH monitoring on the carrier, PDCCHmonitoring for the carrier, start or restart the carrier deactivationtimer associated with the carrier, and/or the like. If the devicereceives an activation/deactivation MAC control element deactivating thecarrier, and/or if the carrier deactivation timer associated with theactivated carrier expires, the base station or device may deactivate thecarrier, and may stop the carrier deactivation timer associated with thecarrier, and/or may flush HARQ buffers associated with the carrier.

If PDCCH on a carrier scheduling the activated carrier indicates anuplink grant or a downlink assignment for the activated carrier, thedevice may restart the carrier deactivation timer associated with thecarrier. When a carrier is deactivated, the wireless device may nottransmit SRS (sounding reference signal) for the carrier, may not reportCQI/PMI/RI for the carrier, may not transmit on UL-SCH for the carrier,may not monitor the PDCCH on the carrier, and/or may not monitor thePDCCH for the carrier.

A process to assign subcarriers to data packets may be executed by a MAClayer scheduler. The decision on assigning subcarriers to a packet maybe made based on data packet size, resources required for transmissionof data packets (number of radio resource blocks), modulation and codingassigned to data packet(s), QoS required by the data packets (i.e. QoSparameters assigned to data packet bearer), the service class of asubscriber receiving the data packet, or subscriber device capability, acombination of the above, and/or the like.

According to some of the various aspects of embodiments, packets may bereferred to service data units and/or protocols data units at Layer 1,Layer 2 and/or Layer 3 of the communications network. Layer 2 in an LTEnetwork may include three sub-layers: PDCP sub-layer, RLC sub-layer, andMAC sub-layer. A layer 2 packet may be a PDCP packet, an RLC packet or aMAC layer packet. Layer 3 in an LTE network may be Internet Protocol(IP) layer, and a layer 3 packet may be an IP data packet. Packets maybe transmitted and received via an air interface physical layer. Apacket at the physical layer may be called a transport block. Many ofthe various embodiments may be implemented at one or many differentcommunication network layers. For example, some of the actions may beexecuted by the PDCP layer and some others by the MAC layer.

According to some of the various aspects of embodiments, subcarriersand/or resource blocks may comprise a plurality of physical subcarriersand/or resource blocks. In another example embodiment, subcarriers maybe a plurality of virtual and/or logical subcarriers and/or resourceblocks.

According to some of the various aspects of embodiments, a radio bearermay be a GBR (guaranteed bit rate) bearer and/or a non-GBR bearer. A GBRand/or guaranteed bit rate bearer may be employed for transfer ofreal-time packets, and/or a non-GBR bearer may be used for transfer ofnon-real-time packets. The non-GBR bearer may be assigned a plurality ofattributes including: a scheduling priority, an allocation and retentionpriority, a portable device aggregate maximum bit rate, and/or the like.These parameters may be used by the scheduler in scheduling non-GBRpackets. GBR bearers may be assigned attributes such as delay, jitter,packet loss parameters, and/or the like.

According to some of the various aspects of embodiments, subcarriers mayinclude data subcarrier symbols and pilot subcarrier symbols. Pilotsymbols may not carry user data, and may be included in the transmissionto help the receiver to perform synchronization, channel estimationand/or signal quality detection. Base stations and wireless devices(wireless receiver) may use different methods to generate and transmitpilot symbols along with information symbols.

According to some of the various aspects of embodiments, the transmitterin the disclosed embodiments of the present invention may be a wirelessdevice (also called user equipment), a base station (also calledeNodeB), a relay node transmitter, and/or the like. The receiver in thedisclosed embodiments of the present invention may be a wireless device(also called user equipment-UE), a base station (also called eNodeB), arelay node receiver, and/or the like. According to some of the variousaspects of embodiments of the present invention, layer 1 (physicallayer) may be based on OFDMA or SC-FDMA. Time may be divided intoframe(s) with fixed duration. Frame(s) may be divided into substantiallyequally sized subframes, and subframe(s) may be divided intosubstantially equally sized slot(s). A plurality of OFDM or SC-FDMAsymbol(s) may be transmitted in slot(s). OFDMA or SC-FDMA symbol(s) maybe grouped into resource block(s). A scheduler may assign resource(s) inresource block unit(s), and/or a group of resource block unit(s).Physical resource block(s) may be resources in the physical layer, andlogical resource block(s) may be resource block(s) used by the MAClayer. Similar to virtual and physical subcarriers, resource block(s)may be mapped from logical to physical resource block(s). Logicalresource block(s) may be contiguous, but corresponding physical resourceblock(s) may be non-contiguous. Some of the various embodiments of thepresent invention may be implemented at the physical or logical resourceblock level(s).

According to some of the various aspects of embodiments, layer 2transmission may include PDCP (packet data convergence protocol), RLC(radio link control), MAC (media access control) sub-layers, and/or thelike. MAC may be responsible for the multiplexing and mapping of logicalchannels to transport channels and vice versa. A MAC layer may performchannel mapping, scheduling, random access channel procedures, uplinktiming maintenance, and/or the like.

According to some of the various aspects of embodiments, the MAC layermay map logical channel(s) carrying RLC PDUs (packet data unit) totransport channel(s). For transmission, multiple SDUs (service dataunit) from logical channel(s) may be mapped to the Transport Block (TB)to be sent over transport channel(s). For reception, TBs from transportchannel(s) may be demultiplexed and assigned to corresponding logicalchannel(s). The MAC layer may perform scheduling related function(s) inboth the uplink and downlink and thus may be responsible for transportformat selection associated with transport channel(s). This may includeHARQ functionality. Since scheduling may be done at the base station,the MAC layer may be responsible for reporting scheduling relatedinformation such as UE (user equipment or wireless device) bufferoccupancy and power headroom. It may also handle prioritization fromboth an inter-UE and intra-UE logical channel perspective. MAC may alsobe responsible for random access procedure(s) for the uplink that may beperformed following either a contention and non-contention basedprocess. UE may need to maintain timing synchronization with cell(s).The MAC layer may perform procedure(s) for periodic synchronization.

According to some of the various aspects of embodiments, the MAC layermay be responsible for the mapping of multiple logical channel(s) totransport channel(s) during transmission(s), and demultiplexing andmapping of transport channel data to logical channel(s) duringreception. A MAC PDU may include of a header that describes the formatof the PDU itself, which may include control element(s), SDUs, Padding,and/or the like. The header may be composed of multiple sub-headers, onefor constituent part(s) of the MAC PDU. The MAC may also operate in atransparent mode, where no header may be pre-pended to the PDU.Activation command(s) may be inserted into packet(s) using a MAC controlelement.

According to some of the various aspects of embodiments, the MAC layerin some wireless device(s) may report buffer size(s) of either a singleLogical Channel Group (LCG) or a group of LCGs to a base station. An LCGmay be a group of logical channels identified by an LCG ID. The mappingof logical channel(s) to LCG may be set up during radio configuration.Buffer status report(s) may be used by a MAC scheduler to assign radioresources for packet transmission from wireless device(s). HARQ and ARQprocesses may be used for packet retransmission to enhance thereliability of radio transmission and reduce the overall probability ofpacket loss.

According to some of the various aspects of embodiments, an RLCsub-layer may control the applicability and functionality of errorcorrection, concatenation, segmentation, re-segmentation, duplicatedetection, in-sequence delivery, and/or the like. Other functions of RLCmay include protocol error detection and recovery, and/or SDU discard.The RLC sub-layer may receive data from upper layer radio bearer(s)(signaling and data) called service data unit(s) (SDU). The transmissionentities in the RLC layer may convert RLC SDUs to RLC PDU afterperforming functions such as segmentation, concatenation, adding RLCheader(s), and/or the like. In the other direction, receiving entitiesmay receive RLC PDUs from the MAC layer. After performing reordering,the PDUs may be assembled back into RLC SDUs and delivered to the upperlayer. RLC interaction with a MAC layer may include: a) data transferfor uplink and downlink through logical channel(s); b) MAC notifies RLCwhen a transmission opportunity becomes available, including the size oftotal number of RLC PDUs that may be transmitted in the currenttransmission opportunity, and/or c) the MAC entity at the transmittermay inform RLC at the transmitter of HARQ transmission failure.

According to some of the various aspects of embodiments, PDCP (packetdata convergence protocol) may comprise a layer 2 sub-layer on top ofRLC sub-layer. The PDCP may be responsible for a multitude of functions.First, the PDCP layer may transfer user plane and control plane data toand from upper layer(s). PDCP layer may receive SDUs from upper layer(s)and may send PDUs to the lower layer(s). In other direction, PDCP layermay receive PDUs from the lower layer(s) and may send SDUs to upperlayer(s). Second, the PDCP may be responsible for security functions. Itmay apply ciphering (encryption) for user and control plane bearers, ifconfigured. It may also perform integrity protection for control planebearer(s), if configured. Third, the PDCP may perform header compressionservice(s) to improve the efficiency of over the air transmission. Theheader compression may be based on robust header compression (ROHC).ROHC may be performed on VOIP packets. Fourth, the PDCP may beresponsible for in-order delivery of packet(s) and duplicate detectionservice(s) to upper layer(s) after handover(s). After handover, thesource base station may transfer unacknowledged packet(s)s to targetbase station when operating in RLC acknowledged mode (AM). The targetbase station may forward packet(s)s received from the source basestation to the UE (user equipment).

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example,” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLab VIEWMathScript. Additionally, it may be possible to implementmodules using physical hardware that incorporates discrete orprogrammable analog, digital and/or quantum hardware. Examples ofprogrammable hardware comprise: computers, microcontrollers,microprocessors, application-specific integrated circuits (ASICs); fieldprogrammable gate arrays (FPGAs); and complex programmable logic devices(CPLDs). Computers, microcontrollers and microprocessors are programmedusing languages such as assembly, C, C++ or the like. FPGAs, ASICs andCPLDs are often programmed using hardware description languages (HDL)such as VHSIC hardware description language (VHDL) or Verilog thatconfigure connections between internal hardware modules with lesserfunctionality on a programmable device. Finally, it needs to beemphasized that the above mentioned technologies are often used incombination to achieve the result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using FDD communication systems. However, one skilled in the art willrecognize that embodiments of the invention may also be implemented inTDD communication systems. The disclosed methods and systems may beimplemented in wireless or wireline systems. The features of variousembodiments presented in this invention may be combined. One or manyfeatures (method or system) of one embodiment may be implemented inother embodiments. Only a limited number of example combinations areshown to indicate to one skilled in the art the possibility of featuresthat may be combined in various embodiments to create enhancedtransmission and reception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112, paragraph 6. Claims that do not expressly include the phrase“means for” or “step for” are not to be interpreted under 35 U.S.C. 112,paragraph 6.

What is claimed is:
 1. A method comprising: receiving, by a first basestation from a wireless device, at least one measurement reportcomprising signal quality information of a subset of a plurality ofcarriers, the wireless device having one connection with the first basestation, the connection being configurable to carry a plurality of callsvia a radio technology, each call being from a call category in aplurality of call categories; and initiating a handover of theconnection to a second base station of the radio technology based oncriteria on the signal quality information, the criteria being employedfor handover at least when the connection comprises a plurality of callsof different call types, the criteria comprising a first criterion and asecond criterion different from the first criterion, the first criterionbeing employed if the connection engages in an active call from thefirst call category, the second criterion being employed if theconnection does not engage in an active call from the first callcategory, wherein: the first call category is a voice call; and thefirst base station is of a different type compared with the second basestation.
 2. The method of claim 1, wherein the call is carried over aradio bearer.
 3. The method of claim 1, wherein the at least onemeasurement report comprises: at least one channel state informationreport; and at least one RRC measurement report.
 4. The method of claim1, wherein each of the first criterion and the second criterionconsiders a relative signal quality value.
 5. The method of claim 4,wherein the relative signal quality value considers a first signalquality value of a first carrier of the first base station and a secondsignal quality value of a second carrier of the second base station. 6.The method of claim 5, wherein the first criterion is based oncomparison of the relative signal quality value with a first thresholdvalue, and the second criterion is based on comparison of the relativesignal quality value with a second threshold value.
 7. The method ofclaim 5, wherein the second signal quality value considers a measuredsignal quality value and a bias value.
 8. The method of claim 1, whereina user of the wireless device is billed differently by a serviceprovider for: calls from the first call category that are carriedthrough the first base station; and calls from the first call categorythat are carried through the second base station.
 9. The method of claim1, wherein: the first base station is a macro base station; and thesecond base station is a femto base station.
 10. The method of claim 1,further comprising transmitting a first control message to a networknode in a wireless network after a handover decision; receiving a secondcontrol message from the network node, the second control messageindicating that the second base station accepted a handover request; andtransmitting a handover command to the wireless device.
 11. The methodof claim 10, further comprising receiving a proximity indication messagefrom the wireless device before transmitting the first control message,the proximity indication message indicating that the wireless deviceentered the proximity of the second base station.
 12. A first basestation comprising: one or more processors; and memory storinginstructions that, when executed, cause the first base station to:receive, from a wireless device, at least one measurement reportcomprising signal quality information of a subset of a plurality ofcarriers, the wireless device having one connection with the first basestation, the connection being configurable to carry a plurality of callsvia a radio technology, each call being from a call category in aplurality of call categories; and initiate a handover of the connectionto a second base station of the radio technology based on criteria onthe signal quality information, the criteria being employed for handoverat least when the connection comprises a plurality of calls of differentcall types, the criteria comprising a first criterion and a secondcriterion different from the first criterion, the first criterion beingemployed if the connection engages in an active call from the first callcategory, the second criterion being employed if the connection does notengage in an active call from the first call category, wherein: thefirst call category is a voice call; and the first base station is of adifferent type compared with the second base station.
 13. The first basestation of claim 12, wherein the call is carried over a radio bearer.14. The first base station of claim 12, wherein the at least onemeasurement report comprises: at least one channel state informationreport; and at least one RRC measurement report.
 15. The first basestation of claim 12, wherein each of the first criterion and the secondcriterion considers a relative signal quality value.
 16. The first basestation of claim 15, wherein the relative signal quality value considersa first signal quality value of a first carrier of the first basestation and a second signal quality value of a second carrier of thesecond base station.
 17. The first base station of claim 16, wherein thefirst criterion is based on comparison of the relative signal qualityvalue with a first threshold value, and the second criterion is based oncomparison of the relative signal quality value with a second thresholdvalue.
 18. The first base station of claim 16, wherein the second signalquality value considers a measured signal quality value and a biasvalue.
 19. The first base station of claim 12, wherein the user of thewireless device is billed differently by a service provider for: callsfrom the first call category that are carried through the first basestation; and calls from the first call category that are carried throughthe second base station.
 20. The first base station of claim 12, whereinthe instructions when executed further cause the base station to receivea proximity indication message from the wireless device beforetransmitting the first control message, the proximity indication messageindicating that the wireless device entered the proximity of the secondbase station.